Biggest thing that helps me is going out on my own and just sessioning sections of trail until I get them dialed. I'll go out and ride the same three turns 15 times in a row, trying to get the flow exactly right, then move on. Same with climbs, I'll just go ride the damn thing until I clear it, or I'm too beat to keep trying. As far as I've found that's the best way to get my fundamentals down. I really like doing that solo, without the pressure of the group to keep going I'm way more comfortable practicing little sections of trail. The only exception to that is jumps, I like being with a crew to hit new jumps and gaps. Last year I helped coach a little kids MTN bike camp and it might have been the best thing I did all summer for my riding. 30 hours of just practicing flat cornering and manuals and such. Not exciting, but building the fundamentals is vital. And good call on the Roscoe, Plus is the way to go if you're just getting started!